The present invention relates generally to the field of reclosable bags and more specifically to reclosable bags that use or incorporate tamper evident, hermetic seal, and reclosable fastener assemblies or mechanisms of the slider, zipper, or press-to-close type. The present invention is particularly concerned with a reclosable bag that may be filled with a food product at a factory or food processing plant and then sealed to protect the food product until such time as a customer purchases the reclosable bag and opens it to access the food product within.
Reclosable, typically flexible, containers are well known in the art. Such containers normally comprise a bag-like structure made from a folded web of material, like thermoplastic film. These types of containers may also include reclosable zipper structures, as well as interlocking male and female zipper elements fused, extruded, or attached to the bag sidewalls. Alternatively, the reclosable zipper structures, mechanisms, or assemblies may also be identified as slider closure systems, i.e., a closure system for slider bags and form, fill and seal technology that contain two tracks that can be interlocked and a separate part (a slider) that rides on the tracks and is used to open and/or close the tracks. The bag-like structure is created when the thermoplastic film is folded, sealed, and severed along its exposed edges.
Reclosable bags are a great convenience to the consumer. This is especially true where the food product or material contained within the bag is of a type that may not all be consumed at once, for example, shredded cheese, sliced cheese, cheese, processed cheese, deli meats, snack foods, vegetables, fruits, sweets, etc. A problem with these types of bags is achieving a design in which the food product is hermetically sealed against oxygen, atmospheric intrusion or transmission, bacteria, molds, and/or other sources of contamination, while also providing features that help to disclose to the consumer evidence of tampering without substantially interfering with the ease of use of the bag.
In addressing this problem it is also desired to achieve a design that is easy to manufacture and may be used in combination with known types of packaging machinery that use form, fill, and seal technology such as Horizontal Form Fill and Seal (HFFS) machines or Vertical Form Fill and Seal (VFFS) machines. It is also desired to achieve a design that may optionally be used in combination with Horizontal Flow Wrapper (HFW) machines; e.g., J-WRAP machines presently available from Jones Automation Company, Inc. of Beloit, Wis.
Tamper evident packaging may also require the use of several pieces of film, which must then be connected to each other. This can make manufacturing of the reclosable bag more complicated.
Gusseted style packages are additionally greatly convenient to the consumer. Gusseted style packages allow the package to stand upright due to their wider base. This is true when it is desirable to stand a package upright by itself. Further, the wider base of the gusseted style package enables them to hold a greater volume of product than a conventional four-sided seal package of similar dimensions. The challenge has been to combine the convenience of a zippered packaged in one gusseted, reclosable bag.
With a “press to close” type zipper, the gusset style package is typically formed with the gusset at the bottom and the zipper at the top. This type of package is filled through the opened zipper. Several problems have arisen during production and filling of this type package. For example, in the package making process, it is necessary for the “press to close” zipper to be closed (i.e. the male and female profiles need to be engaged), when the zipper profiles are fused together at the side seal. If the male and female profiles are not engaged, they are subject to misalignment. If they are mis-aligned at the side seal station, the resulting package will have a zipper that does not close completely, specifically adjacent to the side seal, and a leaky package results. Furthermore, after the side seal is added, the usually simple process of opening the zipper for filling using a stationary blade to plow the zipper open, is no longer a reasonable option. Rather, the zipper must be opened, by either pulling the sides of the package that the zipper is attached to apart, or by holding the sides securely while a plunger lowers into the upper portion of the package, forcing the zipper open. Regardless of the method chosen, an unacceptable percentage of unopened packages or damaged zippers results.
An additional problem encountered by usual top filling of the zippered, gusseted bag, is product waste and contamination of zipper profiles. As a solution to this problem, some filling processes lower a fill tube into the package and past the zipper profiles area in an attempt to protect the profiles from the product. This technique reduces profile contamination, but does not eliminate it. This is because clearance must be maintained between the fill tube and the package walls to ensure consistency of tube insertion and to provide an exit passage for the air of the package that the product is displacing. In the stream of air exiting the package to make room for the product, some product is inevitably included, and profile contamination results.
A further problem associated with traditional top filling of zippered, gusseted packages occurs when the zipper is closed after the package has been filled with product. The usual method forces the zipper closed by applying force to both sides of the zipper and in a direction tangent to the sides of the package. This process may not consistently close the zipper and those that do close may have product pushed into the zipper profiles.
Gusseted packages using a slider type zipper encounter additional filling problems. In filling a package of this type, the slider portion of the zipper must be slid from one side of the package to the other in order to open the profiles. Once the package is filled, the sliding of the slider portion must be reversed to close the top. This process is difficult and expensive, rendering top filling through slider type zippered packages to be commercially impractical.
The closest gusseted package references are believed to be U.S. Pat. No. 5,938,337 issued on 17 Aug. 1999, U.S. Pat. No. 5,529,394 issued on 25 Jun. 1996, and U.S. Pat. No. 5,417,040 issued on 23 May 1995. Although these patents disclose advantageous methods, they fail to fully utilize the benefits of a gusseted type package. Namely, because of the wider base provided in a gusseted bag, they are able to hold a greater volume than conventional four sided seal packages of the same height and width. The above-mentioned patents provide methods for filling the gusseted bag from the gusset side of the package and opposite the closure mechanism. However, when a gusseted bag is filled from the bottom, gusseted side, product stacks upward in the package similarly to filling a conventional four sided package. The result is the inability to fully utilize the added volume benefit that the gusset provides.
It is one of the objectives of the present invention to provide a reclosable bag that may be manufactured using known packaging machinery. As previously, noted, such known machinery includes HFFS machines, VFFS machines, and HFW machines. Additionally, as will be apparent to a person of skill in the art after reading the present disclosure contained herein thermoform type machines like the one disclosed in U.S. Pat. No. 4,240,241 could also be used to practice the present invention disclosed herein, after appropriate modification as the disclosure herein will make apparent.
It is also an objective to perform the manufacturing task using only one piece of parent film in combination with a reclosable zipper assembly.
Further, it is an objective of the invention to provide the manufacturer with the option of including some or all the features of tamper resistance or evidence, hermetic seal, and ease of use in the reclosable bag that is produced.
Another objective, especially with slider or zipper type structures or sliding type zippers or fasteners is ease of use. While a sliding type zipper structure is itself relatively easy to use, the bag structures include sidewalls or fin portions that extend up past the sliding type zipper structure. This interferes with the consumer's access to the food, makes it difficult to see the zipper structure, and also makes it more difficult to easily operate the zipper mechanism. This is especially true if the person opening and closing the bag is disabled, has arthritis, or another aliment, which limits the manual dexterity of that person.
Additionally, increased ease of access to the food product is an objective because the larger the zipper structure and its associated elements the smaller the opening left to the consumer to access the food product.
It is a further objective to provide a reclosable gusseted package that may be side filled with product.
It is another objective to provide a reclosable gusseted package that may be side filled and avoid zipper profile contamination.
It is another objective to provide a reclosable, gusseted package that may be side filled to ensure optimal volumetric filling of the gusseted portion.
It is one of the objectives of the present invention to provide a gusseted reclosable bag that may be manufactured using known packaging machinery, such known machinery includes HFFS machines.
The present invention is believed to address these and other objectives by the unique and simple structures and methods disclosed herein.